It is known in the art of field-oriented (or vector-controlled) motor drives and motor speed controls that such drives and controls require knowledge of the motor parameters such as the rotor time constant (.tau..sub.R), torque constant (K.sub.T *), and rated magnetizing current I.sub.dRATED.
One technique used to determine these motor parameters is to analyze the motor in an engineering laboratory using a dynamometer and expensive test equipment and performing time consuming, highly technical tasks by a skilled technician or engineer. However, in modernization or retrofit applications, where a new drive replaces an older drive in an existing elevator system, it is not convenient or cost effective to remove the motor from the elevator system for evaluation of the motor.
Also, it is desirable to determine the motor parameters based on measurements made on the motor at standstill. While techniques exist to determine the motor parameters while the motor is running (at no-load and under-load), it is not always practical to run such tests in an elevator application. In particular, a no-load test is not practical because this would require unroping the elevator or disconnecting the motor from the gearbox. Further, performing a test under load, i.e., with the motor connected to an elevator, is not practical because it is necessary to have approximately correct motor parameters to start the elevator moving to obtain measurements of the motor running under-load. Also, it is desirable that the technique for determining such motor parameters be wholly contained within the drive control itself, so that field commissioning of retrofit or modernization drives may be performed by installers and service personnel without requiring specific motor/drive tuning skills.